Add access to the user (relogon the user or restart PCDuino afterwards)

sudo usermod -a -G tty ubuntu
sudo usermod -a -G dialout ubuntu

Connect the printer to USB. Check the connection port – command reports the printer is connected to the port ttyUSB0

ll /sys/class/tty/ttyUSB*

Run the OctoPrint server – the command reports the server listens to the port 5000 (hit Ctrl+C to stop it)

~/OctoPrint/venv/bin/octoprint

Open OctoPrint interface in the browser by the address http://xx.xx.xx.xx:5000 (where xx.xx.xx.xx is the IP address of the PCDuino in the local network – replace this with correct address). Follow the instruction to configure and use OctoPrint.